Coffee machines are widely used in our daily work and life. Currently, large coffee machines result in difficulties in maintenance and use due to their huge volume and complex structure, which are not convenient for family and personal use. Currently, small coffee machines are still large since they employ complex elements such as heat exchanger, electromagnetic valve and the like for controlling outflow of heated water from the cavity for boiling water. Some small coffee machines that are merely used to boil water and then brew ground coffee. The quality of the obtained coffee is not consistent.